Fluid injector with syringe engagement mechanism

ABSTRACT

An engagement mechanism associated with a reciprocally movable piston of a fluid injector is configured for releasably engaging an engagement portion at a proximal end of a rolling diaphragm syringe having a flexible sidewall configured for rolling upon itself when acted upon by the piston. The engagement mechanism has a plurality of engagement elements reversibly and pivotally movable about a pivot pin relative to the engagement portion of the syringe between a first position, where the plurality of engagement elements are disengaged from the engagement portion of the syringe, and a second position, where the plurality of engagement elements are pivotally movable about the pivot pin in a radially inward direction to engage with the engagement portion of the syringe. The engagement mechanism further has a drive mechanism for moving the plurality of engagement elements between the first position and the second position.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a § 371 national phase application of PCTInternational Application No. PCT/US2017/056731, filed Oct. 16, 2017,and claims priority to U.S. Provisional Application No. 62/409,044 filedOct. 17, 2016; and U.S. Provisional Application No. 62/545,693, filedAug. 15, 2017, the disclosures of which are incorporated herein byreference in their entirety.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

The present disclosure relates to medical fluid injectors and, moreparticularly, to fluid injectors having syringe engagement mechanismsfor engaging a syringe with a flexible sidewall and a piston engagementportion on a proximal end of the sidewall.

Description of Related Art

In many medical diagnostic and therapeutic procedures, a practitioner,such as a physician, injects a patient with one or more medical fluids.In recent years, a number of injector-actuated syringes and poweredfluid injectors for pressurized injection of medical fluids, such as acontrast solution (often referred to as “contrast”), a flushing agent,such as saline, and other medical fluids, have been developed forprocedures such as angiography, computed tomography (CT), ultrasound,magnetic resonance imaging (MRI), positron emission tomography (PET),and other imaging procedures. In general, these fluid injectors aredesigned to deliver a preset amount of medical fluid at a presetpressure and/or flow rate.

Typically, powered injectors have pistons that connect to a syringeplunger that is slidably disposed within the syringe. The syringegenerally includes a rigid barrel with the syringe plunger beingslidably disposed within the barrel. The piston drives the plunger in adirection of a longitudinal axis of the barrel to draw fluid into thesyringe barrel with a proximal movement of the piston or deliver thefluid from the syringe barrel with a distal movement of the piston.While various connection mechanisms exist in the art for engaging thepiston of the fluid injector with the syringe, it remains desirable todevelop improved designs of syringes and syringe engagement mechanismsto facilitate injection procedures.

SUMMARY OF THE DISCLOSURE

The present disclosure generally relates to fluid injectors having asyringe engagement mechanism for engaging a syringe with a flexiblesidewall and a piston engagement portion on at least a portion of theflexible sidewall.

In some examples of the present disclosure, an engagement mechanism maybe associated with a reciprocally movable piston of a fluid injector.The engagement mechanism may be configured for releasably engaging anengagement portion at a proximal end of a rolling diaphragm syringehaving a flexible sidewall configured for rolling upon itself when actedupon by the piston. The engagement mechanism may have a plurality ofengagement elements reversibly and pivotally movable about a pivot pinrelative to the engagement portion of the syringe between a firstposition, where the plurality of engagement elements are disengaged fromthe engagement portion of the syringe, and a second position, where theplurality of engagement elements are pivotally movable about the pivotpin in a radially inward direction to engage with the engagement portionof the syringe. The engagement mechanism may further have a drivemechanism for moving the plurality of engagement elements between thefirst position and the second position.

In other examples of the present disclosure, the plurality of engagementelements may be progressively movable from the first position to thesecond position with movement of the piston in a proximal direction tocontinuously increase a gripping force on the engagement portion of thesyringe. The drive mechanism may be operatively connected to the pistonsuch that the plurality of engagement elements are movable from thefirst position to the second position with movement of the piston in aproximal direction. The plurality of engagement elements may be movablefrom the second positon to the first position with movement of thepiston in a distal direction. The drive mechanism may move the pluralityof engagement elements between the first position and the secondposition independently of movement of the piston in a proximal directionor a distal direction. The drive mechanism may have at least one of thefollowing: a linear electric motor or actuator, a rotary electric motoror actuator, a solenoid, a pneumatic mechanism, a hydraulic mechanism,an electromagnetic mechanism, an electroactive polymer mechanism, anitinol wire-based mechanism, and any combination thereof. The drivemechanism may have a rod linearly or rotatably movable by a motor.Linear or rotary movement of the rod may reversibly move the pluralityof engagement members between the first position and the secondposition. The plurality of engagement elements may be biased to one ofthe first position or the second position by a biasing mechanism. Thebiasing mechanism may be a spring.

In other examples of the present disclosure, an engagement mechanism maybe associated with a reciprocally movable piston of a fluid injector.The engagement mechanism may be configured for releasably engaging anengagement portion at a proximal end of a rolling diaphragm syringehaving a flexible sidewall configured for rolling upon itself when actedupon by the piston. The engagement mechanism may have a plurality ofengagement elements reversibly and pivotally movable about a pivot pinrelative to the engagement portion of the syringe between a firstposition, where the plurality of engagement elements are disengaged fromthe engagement portion of the syringe, and a second position, where theplurality of engagement elements are pivotally movable about the pivotpin in a radially inward direction to engage with the engagement portionof the syringe. The engagement mechanism may further have a drivemechanism for moving the plurality of engagement elements between thefirst position and the second position. The drive mechanism may have anouter piston sleeve fixed relative to the piston of the fluid injectorand an abutment section movably received within the outer piston sleeveat a distal end of the outer piston sleeve. The abutment section may beoperatively engaged with the plurality of engagement members. The drivemechanism may further have an inner piston sleeve movably receivedwithin the outer piston sleeve and connected with the abutment sectionsuch that movement of the inner piston sleeve causes movement of theabutment section. The inner piston sleeve may be movable by a piston rodmovably coupled to the piston. Movement of the piston in a proximaldirection may moves the outer piston sleeve proximally relative to theabutment section, and proximal movement of the outer piston sleeverelative to the abutment section may move the plurality of engagementmembers from the first position to the second position.

In other examples of the present disclosure, the abutment section has anouter engagement surface configured for contacting a closed end wall ofthe syringe at a central opening on the outer engagement surfaceconfigured for receiving the engagement portion of the syringe. theplurality of engagement elements are progressively movable from thefirst position to the second position with movement of the piston in aproximal direction to continuously increase a gripping force on theengagement portion of the syringe. At least one of the plurality ofengagement elements may have a pointed distal end configured for atleast partially embedding into the engagement portion of the syringewhen the plurality of engagement elements are in the second position.The plurality of engagement elements may be movable from the secondpositon to the first position with movement of the piston in the distaldirection. The plurality of engagement elements may be biased to one ofthe first position or the second position by a biasing mechanism, suchas a spring.

In other examples of the present disclosure, a fluid injector may haveat least one injector head with at least one reciprocally movable pistonand an engagement mechanism associated with the at least one piston andconfigured for releasably engaging an engagement portion at a proximalend of a rolling diaphragm syringe having a flexible sidewall configuredfor rolling upon itself when acted upon by the piston. The engagementmechanism may have a plurality of engagement elements reversibly andpivotally movable about a pivot pin relative to the engagement portionof the syringe between a first position, where the plurality ofengagement elements are disengaged from the engagement portion of thesyringe, and a second position, where the plurality of engagementelements are pivotally movable about the pivot pin in a radially inwarddirection to engage with the engagement portion of the syringe. Thefluid injector may further have a drive mechanism for moving theplurality of engagement elements between the first position and thesecond position.

In other examples of the present disclosure, the drive mechanism mayhave at least one of the following: a linear electric motor or actuator,a rotary electric motor or actuator, a solenoid, a pneumatic mechanism,a hydraulic mechanism, an electromagnetic mechanism, an electroactivepolymer mechanism, a nitinol wire-based mechanism, and any combinationthereof. The drive mechanism may have a rod linearly or rotatablymovable by a motor. Linear or rotary movement of the rod may reversiblymove the plurality of engagement members between the first position andthe second position.

In other examples of the present disclosure, the drive mechanism mayhave an outer piston sleeve fixed relative to the piston of the fluidinjector and an abutment section movably received within the outerpiston sleeve at a distal end of the outer piston sleeve. The abutmentsection may be operatively engaged with the plurality of engagementmembers. The drive mechanism may further have an inner piston sleevemovably received within the outer piston sleeve and connected with theabutment section such that movement of the inner piston sleeve causesmovement of the abutment section. The inner piston sleeve may be movableby a piston rod movably coupled to the piston. Movement of the piston ina proximal direction may move the outer piston sleeve proximallyrelative to the abutment section. Proximal movement of the outer pistonsleeve relative to the abutment section may move the plurality ofengagement members from the first position to the second position.

Various other examples of the present disclosure are recited in one ormore of the following enumerated clauses:

Clause 1: An engagement mechanism associated with a reciprocally movablepiston of a fluid injector and configured for releasably engaging anengagement portion at a proximal end of a rolling diaphragm syringehaving a flexible sidewall configured for rolling upon itself when actedupon by the piston, the engagement mechanism comprising: a plurality ofengagement elements reversibly and pivotally movable about a pivot pinrelative to the engagement portion of the syringe between a firstposition, where the plurality of engagement elements are disengaged fromthe engagement portion of the syringe, and a second position, where theplurality of engagement elements are pivotally movable about the pivotpin in a radially inward direction to engage with the engagement portionof the syringe; and a drive mechanism for moving the plurality ofengagement elements between the first position and the second position.

Clause 2: The engagement mechanism of clause 1, wherein the plurality ofengagement elements are progressively movable from the first position tothe second position with movement of the piston in a proximal directionto continuously increase a gripping force on the engagement portion ofthe syringe.

Clause 3: The engagement mechanism of clauses 1 or 2, wherein the drivemechanism is operatively connected to the piston such that the pluralityof engagement elements are movable from the first position to the secondposition with movement of the piston in a proximal direction.

Clause 4: The engagement mechanism of clause 3, wherein the plurality ofengagement elements are movable from the second positon to the firstposition with movement of the piston in a distal direction.

Clause 5: The engagement mechanism of clauses 1 or 2, wherein the drivemechanism moves the plurality of engagement elements between the firstposition and second position independently of movement of the piston ina proximal direction or a distal direction.

Clause 6: The engagement mechanism of any of clauses 1 to 5, wherein thedrive mechanism comprises at least one of the following: a linearelectric motor or actuator, a rotary electric motor or actuator, asolenoid, a pneumatic mechanism, a hydraulic mechanism, anelectromagnetic mechanism, an electroactive polymer mechanism, a nitinolwire-based mechanism, and any combination thereof.

Clause 7: The engagement mechanism of any of clauses 1 to 6, wherein thedrive mechanism comprises a rod linearly or rotatably movable by amotor, and wherein linear or rotary movement of the rod reversibly movesthe plurality of engagement members between the first position and thesecond position.

Clause 8: The engagement mechanism of any of clauses 1 to 7, wherein theplurality of engagement elements are biased to one of the first positionor the second position by a biasing mechanism.

Clause 9: The engagement mechanism of clauses 8, wherein the biasingmechanism is a spring.

Clause 10: An engagement mechanism associated with a reciprocallymovable piston of a fluid injector and configured for releasablyengaging an engagement portion at a proximal end of a rolling diaphragmsyringe having a flexible sidewall configured for rolling upon itselfwhen acted upon by the piston, the engagement mechanism comprising: aplurality of engagement elements reversibly and pivotally movable abouta pivot pin relative to the engagement portion of the syringe between afirst position, where the plurality of engagement elements aredisengaged from the engagement portion of the syringe, and a secondposition, where the plurality of engagement elements are pivotallymovable about the pivot pin in a radially inward direction to engagewith the engagement portion of the syringe; and a drive mechanism formoving the plurality of engagement elements between the first positionand the second position, the drive mechanism comprising: an outer pistonsleeve fixed relative to the piston of the fluid injector; an abutmentsection movably received within the outer piston sleeve at a distal endof the outer piston sleeve, wherein the abutment section is operativelyengaged with the plurality of engagement members; and an inner pistonsleeve movably received within the outer piston sleeve and connectedwith the abutment section such that movement of the inner piston sleevecauses movement of the abutment section, wherein the inner piston sleeveis movable by a piston rod movably coupled to the piston, whereinmovement of the piston in a proximal direction moves the outer pistonsleeve proximally relative to the abutment section, and wherein proximalmovement of the outer piston sleeve relative to the abutment sectionmoves the plurality of engagement members from the first position to thesecond position.

Clause 11: The engagement mechanism of clause 10, wherein the abutmentsection has an outer engagement surface configured for contacting aclosed end wall of the syringe at a central opening on the outerengagement surface configured for receiving the engagement portion ofthe syringe.

Clause 12: The engagement mechanism of clauses 10 or 11, wherein theplurality of engagement elements are progressively movable from thefirst position to the second position with movement of the piston in aproximal direction to continuously increase a gripping force on theengagement portion of the syringe.

Clause 13: The engagement mechanism of any of clauses 10 to 12, whereinat least one of the plurality of engagement elements has a pointeddistal end configured for at least partially embedding into theengagement portion of the syringe when the plurality of engagementelements are in the second position.

Clause 14: The engagement mechanism of any of clauses 10 to 13, whereinthe plurality of engagement elements are movable from the second positonto the first position with movement of the piston in the distaldirection.

Clause 15: The engagement mechanism of any of clauses 10 to 14, whereinthe plurality of engagement elements are biased to one of the firstposition or the second position by a biasing mechanism.

Clause 16: The engagement mechanism of clause 15, wherein the biasingmechanism is a spring.

Clause 17: A fluid injector comprising: at least one injector headcomprising at least one reciprocally movable piston; an engagementmechanism associated with the at least one piston and configured forreleasably engaging an engagement portion at a proximal end of a rollingdiaphragm syringe having a flexible sidewall configured for rolling uponitself when acted upon by the piston, the engagement mechanismcomprising: a plurality of engagement elements reversibly and pivotallymovable about a pivot pin relative to the engagement portion of thesyringe between a first position, where the plurality of engagementelements are disengaged from the engagement portion of the syringe, anda second position, where the plurality of engagement elements arepivotally movable about the pivot pin in a radially inward direction toengage with the engagement portion of the syringe; and a drive mechanismfor moving the plurality of engagement elements between the firstposition and the second position.

Clause 18: The fluid injector of clause 17, wherein the drive mechanismcomprises at least one of the following: a linear electric motor oractuator, a rotary electric motor or actuator, a solenoid, a pneumaticmechanism, a hydraulic mechanism, an electromagnetic mechanism, anelectroactive polymer mechanism, a nitinol wire-based mechanism, and anycombination thereof.

Clause 19: The fluid injector of clauses 17 or 18, wherein the drivemechanism comprises a rod linearly or rotatably movable by a motor, andwherein linear or rotary movement of the rod reversibly moves theplurality of engagement members between the first position and thesecond position.

Clause 20: The fluid injector of clause 17, wherein the drive mechanismcomprises: an outer piston sleeve fixed relative to the piston of thefluid injector; an abutment section movably received within the outerpiston sleeve at a distal end of the outer piston sleeve, wherein theabutment section is operatively engaged with the plurality of engagementmembers; and an inner piston sleeve movably received within the outerpiston sleeve and connected with the abutment section such that movementof the inner piston sleeve causes movement of the abutment section,wherein the inner piston sleeve is movable by a piston rod movablycoupled to the piston, wherein movement of the piston in a proximaldirection moves the outer piston sleeve proximally relative to theabutment section, and wherein proximal movement of the outer pistonsleeve relative to the abutment section moves the plurality ofengagement members from the first position to the second position.

Further details and advantages of the various examples described indetail herein will become clear upon reviewing the following detaileddescription in conjunction with the accompanying drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of a fluid injector having a pair ofpressure jackets and syringes in accordance with one example of thepresent disclosure;

FIG. 2A is a side cross-sectional view of a syringe in accordance withone example of the present disclosure, with the syringe shown in anunrolled configuration;

FIG. 2B is a side cross-sectional view of the syringe of FIG. 2A shownin a rolled configuration;

FIG. 3A is a side cross-sectional view of a syringe and a piston havinga syringe engagement mechanism in accordance with one example of thepresent disclosure shown in an open state or configuration;

FIG. 3B is a side cross-sectional view of the syringe and the pistonwith the syringe engagement mechanism of FIG. 3A shown in a closed stateor configuration;

FIG. 4A is a side cross-sectional view of a syringe and a piston havinga syringe engagement mechanism in accordance with one example of thepresent disclosure;

FIG. 4B is an exploded view of the piston and the syringe with theengagement mechanism shown in FIG. 4A;

FIG. 5A is a side cross-sectional view of a syringe and a piston havinga syringe engagement mechanism in accordance with one example of thepresent disclosure shown in an open state or configuration;

FIGS. 5B-5C are side cross-sectional views of the syringe and the pistonwith the syringe engagement mechanism of FIG. 5A showing movement of thesyringe engagement mechanism from the open state or configuration to aclosed state or configuration;

FIGS. 5D-5E are side cross-sectional views of the syringe and the pistonwith the syringe engagement mechanism of FIG. 5A showing movement of thesyringe engagement mechanism from the closed state or configuration tothe open state or configuration;

FIGS. 6A-6C are side views of engagement arms of a syringe engagementmechanism in accordance with one example of the present disclosureshowing movement of the engagement arms between an open state orconfiguration and a closed state or configuration;

FIG. 7A is a side cross-sectional view of a syringe and a piston havinga syringe engagement mechanism in accordance with one example of thepresent disclosure shown in an open state or configuration;

FIG. 7B is a side cross-sectional view of the syringe and the pistonwith the syringe engagement mechanism of FIG. 7A shown in a closed stateor configuration;

FIG. 8A is a side cross-sectional view of a syringe and a piston havinga syringe engagement mechanism in accordance with one example of thepresent disclosure shown in an open state or configuration;

FIG. 8B is a side cross-sectional view of the syringe and the pistonwith the syringe engagement mechanism of FIG. 8A shown in a closed stateor configuration;

FIG. 8C is a side cross-sectional view of the syringe and the pistonwith the syringe engagement mechanism of FIG. 8A shown in the open stateor configuration;

FIG. 9A is a side cross-sectional view of a syringe and a piston havinga syringe engagement mechanism in accordance with one example of thepresent disclosure shown in an open state or configuration;

FIG. 9B is a side cross-sectional view of the syringe and the pistonwith the syringe engagement mechanism of FIG. 9A shown in a closed stateor configuration;

FIGS. 9C-9D are side cross-sectional views of the syringe and the pistonwith the syringe engagement mechanism of FIG. 9A showing movement of thesyringe engagement mechanism from the closed state or configuration tothe open state or configuration;

FIG. 10A is a perspective, partial cross-sectional view of a syringe anda piston having a syringe engagement mechanism in accordance with oneexample of the present disclosure shown in an open state orconfiguration;

FIG. 10B is a side cross-sectional view of the syringe and the pistonwith the syringe engagement mechanism shown in FIG. 10A;

FIG. 10C is a perspective, partial cross-sectional view of the syringeand the piston with the syringe engagement mechanism shown in FIG. 10Awith the syringe engagement mechanism shown in a closed state orconfiguration;

FIG. 10D is a side cross-sectional view of the syringe and the pistonwith the syringe engagement mechanism shown in FIG. 10C;

FIG. 10E is a side cross-sectional view of a syringe and a piston havinga syringe engagement mechanism in accordance with one example of thepresent disclosure shown in an open state or configuration;

FIG. 10F is a side cross-sectional view of the syringe and the pistonwith the syringe engagement mechanism shown in FIG. 10E with the syringeengagement mechanism shown in a closed state or configuration;

FIG. 10G is a side cross-sectional view of a syringe and a piston havinga syringe engagement mechanism in accordance with one example of thepresent disclosure shown in an open state or configuration;

FIG. 10H is a side cross-sectional view of the syringe and the pistonwith the syringe engagement mechanism shown in FIG. 10G with the syringeengagement mechanism shown in a closed state or configuration;

FIG. 11A is a perspective, partial cross-sectional view of a syringe anda piston having a syringe engagement mechanism in accordance with oneexample of the present disclosure shown in an open state orconfiguration;

FIG. 11B is a side cross-sectional view of the syringe and the pistonwith the syringe engagement mechanism shown in FIG. 11A;

FIG. 11C is a perspective, partial cross-sectional view of the syringeand piston with the syringe engagement mechanism shown in FIG. 11A withthe syringe engagement mechanism shown in a closed state orconfiguration;

FIG. 11D is a side cross-sectional view of the syringe and the pistonwith the syringe engagement mechanism shown in FIG. 11C;

FIG. 12 is a side cross-sectional view of a syringe and a piston havinga syringe engagement mechanism in accordance with one example of thepresent disclosure; and

FIG. 13 is a side cross-sectional view of a syringe and a piston havinga syringe engagement mechanism in accordance with one example of thepresent disclosure.

DETAILED DESCRIPTION

As used in the specification, the singular form of “a”, “an”, and “the”include plural referents unless the context clearly dictates otherwise.

For purposes of the description hereinafter, the terms “upper”, “lower”,“right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, “lateral”,“longitudinal”, and derivatives thereof shall relate to the disclosureas it is oriented in the drawing figures.

Spatial or directional terms, such as “left”, “right”, “inner”, “outer”,“above”, “below”, and the like, are not to be considered as limiting asthe invention can assume various alternative orientations.

When used in relation to a syringe and/or a pressure jacket, the term“proximal” refers to a portion of a syringe and/or a pressure jacketnearest to an injector when a syringe and/or a pressure jacket isoriented for connecting to an injector.

The term “distal” refers to a portion of a syringe and/or pressurejacket farthest away from an injector when a oriented for connecting tothe injector.

The term “radial” refers to a direction in a cross-sectional planenormal to a longitudinal axis of a syringe and/or pressure jacketextending between proximal and distal ends.

The term “circumferential” refers to a direction around an inner orouter surface of a sidewall of a syringe and/or a pressure jacket.

The term “axial” refers to a direction along a longitudinal axis of asyringe and/or a pressure jacket extending between the proximal anddistal ends.

The term “flexible”, when used in connection with a syringe, means thatat least a portion of a syringe, such as a sidewall of a syringe, iscapable of bending or being bent, for example up to 180°, to change adirection in which it extends.

The terms “roll over”, “rolling over”, and “rolls upon itself” refer toan ability of a first portion of a syringe, such as a proximal portionof a sidewall of a syringe, to bend approximately 180° relative to asecond portion of a syringe, such as a distal portion of a sidewall of asyringe, when urged by a piston of a fluid injector.

All numbers used in the specification and claims are to be understood asbeing modified in all instances by the term “about”. The term “about”means a range of plus or minus ten percent of the stated value.

Unless otherwise indicated, all ranges or ratios disclosed herein are tobe understood to encompass any and all subranges or subratios subsumedtherein. For example, a stated range or ratio of “1 to 10” should beconsidered to include any and all subranges between (and inclusive of)the minimum value of 1 and the maximum value of 10; that is, allsubranges or subratios beginning with a minimum value of 1 or more andending with a maximum value of 10 or less, such as but not limited to, 1to 6.1, 3.5 to 7.8, and 5.5 to 10.

The term “at least” means “greater than or equal to”.

The term “includes” is synonymous with “comprises”.

It is to be understood that the specific devices and processesillustrated in the attached drawings, and described in the followingspecification, are simply exemplary examples of the disclosure. Hence,specific dimensions and other physical characteristics related to theexamples disclosed herein are not to be considered as limiting.

All documents, such as but not limited to issued patents and patentapplications, referred to herein, and unless otherwise indicated, are tobe considered to be “incorporated by reference” in their entirety.

Referring to the drawings in which like reference characters refer tolike parts throughout the several views thereof, the present disclosureis generally directed to fluid injectors having a syringe engagementmechanism for engaging a syringe with a flexible sidewall and a pistonengagement portion on at least a portion of the flexible sidewall. Thesyringe engagement mechanism has a plurality of engagement elementsmovable in a radial direction relative to the engagement portion of thesyringe from a first position, wherein the plurality of engagementelements are disengaged from the engagement portion of the syringe, anda second position, wherein the plurality of engagement elements areengaged with the engagement portion of the syringe.

With reference to FIG. 1 , a fluid injector 10 includes at least oneinjector head 12 and an injector housing 14. The injector 10 may besupported on a support structure 13. In some examples, as shown in FIG.1 , the fluid injector 10 may include two injector heads 12 arranged ina side-by-side orientation. Each injector head 12 may be formed at afront end of the injector housing 14 and may be configured for receivingand retaining at least one pressure jacket 16. While FIG. 1 illustratesthe fluid injector 10 with two injector heads 12, each with acorresponding pressure jacket 16, other examples of the fluid injector10 may include a single injector head 12 and a corresponding pressurejacket 16 or more than two injector heads 12 with a corresponding numberof pressure jackets 16. The pressure jacket 16 may be removably attachedto the injector head 12 with one or more engagement elements, forexample the one or more engagement elements described in PCTInternational Publications WO 2016/069714 and WO 2016/069711, thedisclosures of which are incorporated herein by this reference.

Each injector head 12 includes a drive member, such as a reciprocallydriven piston 19 (shown in FIGS. 3A-3B), moved by a motor, the movementof which is controlled by a controller. Each piston 19 may be configuredto extend into and from the respective injector head 12 through anopening in the front end of the injector housing 14. Each piston 19imparts a motive force to at least a portion of the syringe or to aplunger within the syringe disposed in the respective pressure jacket16, as described herein.

With continued reference to FIG. 1 , the fluid injector 10 is configuredto receive a syringe 20 within each pressure jacket 16. The at least onepressure jacket 16 is typically a reusable component, while the syringe20 is typically a single-use component. In some examples, the syringe 20may be a multi-use component. The fluid injector 10 may have at leastone bulk fluid source for filling the syringes 20 with fluid. At leastone fluid path set may be fluidly connected with a discharge end of eachsyringe 20 for delivering fluid from the syringes 20 through tubingconnected to a catheter, needle, or other fluid delivery connection (notshown) inserted into a patient at a vascular access site. Fluid flowinto and from the at least one syringe 20 may be regulated by a fluidcontrol module (not shown). The fluid control module may operate variouspistons, valves, and/or flow regulating structures to regulate thedelivery of the medical fluid, such as saline solution and contrast, tothe patient based on user selected injection parameters, such asinjection flow rate, duration, total injection volume, and/or ratio ofcontrast media and saline. Examples of suitable front-loading fluidinjectors that may be used or modified for use with the herein-describedsystem, including at least one pressure jacket 16 and syringe 20, aredisclosed in PCT Application Publication No. WO 2015/164783 and PCTApplication Publication No. WO 2016/172467, the disclosures of which areincorporated herein by reference.

With reference to FIGS. 2A-2B, in certain examples, the syringe 20generally includes a hollow body 25 defining an interior volume 27. Thebody 25 has a forward or distal end 28, a rearward or proximal end 30,and a flexible sidewall 32 extending therebetween. The sidewall 32 ofthe syringe 20 defines a soft, pliable or flexible, yet self-supportingbody that is configured to roll upon itself, as a rolling diaphragm,under the action of the piston 19. In particular, the sidewall 32 isconfigured to roll such that its outer surface is folded and inverted ina radially inward direction as the piston 19 is moved in a distaldirection (FIG. 2B) and unrolled and unfolded in the opposite manner ina radially outward direction as the piston 19 is retracted in a proximaldirection (FIG. 2A). The sidewall 32 may have a smooth, substantiallyuniform structure, or it may have one or more ribs provided thereon tofacilitate the rollover during an injection procedure. In some examples,the sidewall 32 and/or the end wall 34 may have a textured surface, or acombination of a smooth surface and a textured surface. One or moreindicia (not shown) may be formed on the sidewall 32. In some examples,the sidewall 32 may have a uniform thickness along its longitudinallength. In other examples, the sidewall 32 may have a non-uniformthickness along its longitudinal length. In specific examples, thesidewall 32 at or near the distal end 28 may be substantially rigid. Aswill be understood by one of skill in the art in view of the presentdisclosure, the engagement mechanisms described herein may also be usedto engage a plunger slidably disposed within the barrel of a syringe,such as described, for example in U.S. Pat. Nos. 6,652,489; 9,173,995;and 9,199,033, the disclosures of which are incorporated by referenceherein. According to these embodiments, the plunger may have a pistonengagement portion, such as described herein, located on a proximal endof the plunger to interact with the plurality of engagement elements ofthe various embodiments of the engagement mechanisms described herein.

With continued reference to FIGS. 2A-2B, the rearward or proximalportion of the sidewall 32 connects to a closed end wall 34, and aforward or distal portion 28 of the sidewall 32 defines a discharge neck36 opposite the closed end wall 34. The closed end wall 34 may have aconcave shape to facilitate the initiation of the inversion or rollingof the sidewall 32 and/or to provide a receiving pocket to receive adistal end of piston 19. For example, the closed end wall 34 may definea receiving end pocket 38 for interfacing directly with asimilarly-shaped piston 19. In particular examples, at least a portionof the piston 19 may be shaped to substantially match the shape of theclosed end wall 34 or, alternatively, pressure from the piston 19 as itis moved distally may conform the end wall 34 to substantially match theshape of at least a portion of the piston 19. The closed end wall 34 mayhave a non-uniform thickness, for example in a radial directionextending from a central longitudinal axis of the syringe 20. In certainexamples, at least a portion of the end wall 34 may be thicker near thecenter and thinner near the connection with the sidewall 32.

With continued reference to FIGS. 2A-2B, the body 25 of the syringe 20is adapted to be removably received in the interior portion of thepressure jacket 16. The distal end 28 of the syringe 20 may be securedremovably or permanently to a cap (not shown), removably attachable tothe pressure jacket 16, or configured with a retention surface tointeract with a retaining force to retain the syringe 20 within thepressure jacket 16. For example, the syringe 20 may be secured to thecap by an adhesive, solvent welding, or laser welding, or be removablysecured to the cap, such as by a friction fit connection or othersuitable mechanical connection. The distal end 28 may have afrusto-conical shape that gradually narrows from the sidewall 32 to thedischarge neck 36. In certain examples, the discharge neck 36 mayterminate in a discharge port 40 having a connection member 42 forconnecting to a cap, fluid path set, or other connection element. Insome examples, the connection member 42 is a threaded interface havingone or more threads. In other examples, the connection member 42 mayhave a luer-type connection. In further examples, the side wall 32 mayhave one or more lips or grooves that interact with correspondinggrooves or lips on the pressure jacket 16 to releasably ornon-releasably retain the syringe 20 within the pressure jacket 16.

The outer diameter of the syringe 20 may be dimensioned such that thesyringe 20 fits within the interior space defined by the throughbore andinner surface of the pressure jacket 16. In one example, the syringe 20fits snuggly but removably within the pressure jacket 16 such that theouter surface of the syringe 20 abuts at least a portion of the innersurface of the walls of the pressure jacket 16. In another example, thesyringe 20 fits loosely within the pressure jacket 16 such that there isa gap between at least a portion of the outer surface of the syringe 20and the inner surface of the pressure jacket 16. The syringe 20 may beexpanded under pressure during an injection procedure such that theouter surface of the syringe 20 abuts the inner surface of the pressurejacket 16. Examples of suitable pressure jacket features are describedin PCT International Application No. PCT/US2017/051473, the disclosureof which is incorporated herein by this reference.

The end wall 34 may have a central portion 44 having a substantiallydome-shaped structure and a piston engagement portion 46 (hereinafterreferred to as “engagement portion 46”) extending proximally from thecentral portion 44. In some examples, the engagement portion 46 mayextend in a proximal direction along a longitudinal axis of the syringe20 from an approximate midpoint of the central portion 44. In someexamples, a diameter of the engagement portion 46 may be uniform, suchthat the engagement portion 46 has a substantially cylindricalstructure. In other examples, the diameter of the engagement portion 46may be non-uniform. For example, the diameter of the engagement portion46 may gradually decrease or increase in the proximal direction. Whilethe engagement portion 46 is shown in FIGS. 2A-2B as being substantiallyflush with the proximal end 30 of the syringe 20, in certain examplesthe engagement portion 46 may extend proximally beyond the proximal end30 of the syringe 20.

The engagement portion 46 may be monolithically formed with the syringebody 25, or it may be removably or non-removably attached to the centralportion 44 of the end wall 34, such as by welding, adhesion, or clipattachment, or other fastening mechanism. The engagement portion 46 isconfigured for interacting with an engagement mechanism on the piston 19of the fluid injector 10, as described herein.

The syringe 20 may be made of any suitable medical-grade plastic orpolymeric material, desirably a clear or substantially translucentplastic material. The material of the syringe 20 is desirably selectedto meet the required tensile and planar stress requirements, water vaportransmission, and chemical/biological compatibility.

In certain embodiments, suitable syringes 20 include a rollingdiaphragm-type syringe as described in WO 2015/164783 and WO 2016/172467having a flexible thin sidewall which rolls upon itself when acted uponby the piston 19 such that an outer surface of the sidewall at a foldingregion is folded in a radially inward direction as the piston 19 isadvanced from the proximal end to the distal end 28 and such that theouter surface of the sidewall 32 at the folding region is unfolded in aradially outward direction as the piston 19 is retracted from the distalend 28 toward the proximal end 30. Such rolling diaphragm syringes maybe made from a suitable medical-grade plastic and have a sidewallthickness ranging from 0.0050 inches to 0.20 inches, or in otherembodiments from 0.010 inches-0.15 inches. Upon pressurization of thesyringe 20 by distal movement of the piston 19, the fluid pressurewithin the rolling diaphragm syringe causes the sidewall to expandradially outward. This effect is enhanced by the relative thinness ofthe syringe sidewall compared to conventional syringes. As the syringesidewall expands radially outward, it contacts the interior surface ofthe pressure jacket 16, which limits further expansion of the syringesidewall, thereby preventing breaking of the syringe wall.

FIGS. 3A-3B show the syringe 20 in combination with a syringe engagementmechanism 48 (hereinafter referred to as “engagement mechanism 48”) ofthe piston 19 in accordance with one example of the present disclosure.The components of the syringe 20 shown in FIGS. 3A-3B are substantiallysimilar to the components of the syringe 20 described herein withreference to FIGS. 2A-2B. The engagement portion 46 of the syringe 20 isconfigured for interacting with one or more engagement pins or surfacesof the engagement mechanism 48 that reversibly move radially inward andoutward to engage and disengage, respectively, the engagement portion 46of the syringe 20.

In various examples, the engagement mechanism 48 has one or moreengagement elements 56, such as engagement fingers or surfaces, movablein a radial direction relative to the engagement 46 portion of thesyringe 20 between a first position, where the plurality of engagementelements 56 are disengaged from the engagement portion 46 of the syringe20, and a second position, where the plurality of engagement elements 56are engaged with the engagement portion 46 of the syringe 20. Theengagement mechanism 48 further has a drive mechanism for moving theplurality of engagement elements 56 such as fingers or surfaces betweenthe first position and the second position.

In various examples, the inward/outward radial movement of theengagement elements 56 may be effected by a proximal/distal movement ofthe piston 19. The engagement elements 56 may be moved radiallyinward/outward via linear movement, arcuate movement, or a combinationof linear and arcuate movement. In various examples, movement of thepiston 19 in the proximal direction may cause the engagement elements 56to contact and lock onto the engagement portion 46 of the syringe 20 sothat the distal end 30 of the syringe 20 may be pulled by the piston 19in a proximal direction to fill the syringe 20 with a medical fluid.Conversely, movement of the piston 19 in a distal direction may causethe engagement elements 56 to be released from contacting the engagementportion 46 of the syringe 20 such that the syringe 20 may be removedfrom the pressure jacket 16 and the injector 10. In various examples,the piston 19 and/or the engagement elements 56 may be movable by amotor drive, a solenoid drive, a pneumatic drive, a hydraulic drive, ordue to an activation of an electro-active polymer, an electromagneticmechanism, or a nitinol wire or other shape memory alloy-basedmechanism, as discussed herein.

With continued reference to FIGS. 3A-3B, the drive mechanism of theengagement mechanism 48 is contained at least partially within thepiston 19. In some examples, the drive mechanism has a plurality ofparts operatively connected with the piston 19 for moving the pluralityof engagement elements 56 between the first position and the secondposition. In some examples, the drive mechanism has an outer pistonsleeve 50 and an abutment section 52 movably received within the outerpiston sleeve 50 at a distal end thereof. The outer piston sleeve 50 hasa substantially cylindrical structure with an open proximal end and anopen distal end. The abutment section 52 has an outer engagement surface54 at its distal end for engaging at least a portion of the distalsurface of central portion 44 of the syringe 20 when the piston 19 isadvanced distally to engage with the syringe 20. In some examples, theabutment section 52 of the piston 19 may contact at least a portion ofthe proximal end 30 of the syringe 20, such as the distal surface ofcentral portion 44 of the end wall 34. The outer engagement surface 54may be shaped to correspond to the shape of the end wall 34 such thatthe outer engagement surface 54 is in surface-to-surface contact with atleast a portion of the end wall 34 of the syringe 20. The outerengagement surface 54 and outer piston sleeve 50 define a surface overwhich the sidewall 32 of the syringe 20 may roll over during a fluidfilling or a fluid delivery process due to proximal or distal movementof the piston 19, respectively. An opening 55 is formed in a centralportion of the abutment section 52. The opening 55 is configured toreceive at least a portion of the engagement portion 46 of the syringe20 when the abutment section 52 substantially contacts the end wall 34of syringe 20. Desirably, an inner diameter of the opening 55 is largerthan an outer diameter of the widest portion of the engagement portion46 to allow free insertion of the engagement portion 46 into the opening55 during distal movement of the piston 19 toward the end wall 34 ofsyringe 20 or proximal movement of the end wall 34 of syringe 20 towardthe piston 19, for example during insertion of the syringe 20 into thepressure jacket 16.

The abutment section 52 is axially movable relative to the outer pistonsleeve 50, which is held in a substantially fixed position, for exampledue to friction between the outer piston sleeve 50 and the piston. Theabutment section 52 is movable or slidable in an axial directionrelative to the outer piston sleeve 50 to control the state or positionof one or more engagement elements 56, such as one or more engagementelements, as described herein. The movement of the abutment section 52relative to the outer piston sleeve 50 is configured to allow engagementor disengagement of the one or more engagement elements 56 with theengagement portion 46 of the syringe 20.

The piston 19 also has an inner piston sleeve 58 that is axially movablerelative to the outer piston sleeve 50. The inner piston sleeve 58 isconnected to the abutment section 52 such that movement of the abutmentsection 52 results in a corresponding movement of the inner pistonsleeve 58, and vice versa. A collar 60 is fixedly mounted within theouter piston sleeve 50. In some examples, the collar 60 may have acircumferential recess 59 that is configured to engage a projection 61protruding from an inner surface of the outer piston sleeve 50. Thecollar 60 has a longitudinal opening 66 configured to receive at least aportion of the engagement portion 46 of the syringe 20. An innerdiameter of the longitudinal opening 66 may be larger than an outerdiameter of the widest portion of the engagement portion 46 to allowfree insertion of the engagement portion 46 into longitudinal opening66.

With continued reference to FIGS. 3A-3B, the abutment section 52 isconnected to the inner piston sleeve 58, such as by one or morefasteners 57 (shown in FIG. 4B). In this manner, axial movement of theinner piston sleeve 58 results in a corresponding axial movement of theabutment section 52, and vice versa.

The inner piston sleeve 58 and the abutment section 52 are movable orslidable in an axial direction relative to the outer piston sleeve 50and the collar 60 with movement of the piston rod 64. For example, theinner piston sleeve 58 and the abutment section 52 may be movablebetween a first position (FIG. 3A), where the one or more engagementelements 56 are disengaged from the engagement portion 46 of the syringe20 and a second position (FIG. 3B), wherein the one or more engagementelements 56 are engaged with the engagement portion 46. In someexamples, the inner piston sleeve 58 and the abutment portion 52 may bebiased to the second position by a biasing mechanism, such as a spring76. A biasing force of the spring 76 may be adjustable by moving theadjustment element 77 in a distal direction (to increase the biasingforce) or in a proximal direction (to reduce the biasing force) or viceversa. The adjustment element 77 may be a screw that is threadablyengaged with the collar 60 such that the spring 76 is disposed betweenthe head of the screw and the proximal surface of the inner pistonsleeve 58 or a washer 81 abutting the proximal surface of the innerpiston sleeve 58. The adjustment element 76 desirably extends through anopening in the inner piston sleeve 58. In some examples, inner pistonsleeve 58 and the abutment section 52 may be movable or slidable in anaxial direction relative to the outer piston sleeve 50 and the collar 60by way of an electrical, pneumatic, electromagnetic, electroactivepolymer-based, shape memory alloy-based or hydraulic actuation mechanismthat is operable independent of the direction of movement of the piston19.

The motion of the abutment section 52 relative to the outer pistonsleeve 50 and the collar 60 is limited to allow engagement ordisengagement of the one or more engagement elements 56 with theengagement portion 46 of the syringe 20. For example, with reference toFIG. 4A, such relative motion can be limited using a metal rod, polymerrod, or dowel 63 fixed to the piston rod 64, where the dowel 63 passesthrough and seats within a slot 65 (shown in FIG. 4B) formed in theinner piston sleeve 58 that is directly connected to the collar 60 andthe abutment section 52. In some examples, the abutment section 52 maybe movable by about 0.100 to 0.150 inches, for example 0.125 inches,with the movement of the inner piston sleeve 58 before the outer pistonsleeve 50 and the abutment section 52 move at the same time. In someexamples, the inner piston sleeve 58 may be in frictional contact withan inner sidewall of the injector head (not shown). This frictionalcontact may be used to restrain the inner piston sleeve 58 whileallowing the piston rod 64 to move, thereby moving the dowel 63 withinthe slot 65. Once the dowel 63 engages the proximal or distal end of theslot 65, the frictional force holding the inner piston sleeve 58 isovercome, and the piston rod 64 and the inner piston sleeve 58 may bemoved together.

Using this range of movement of the abutment section 52, the collar 60,and the inner piston sleeve 58 relative to the piston rod 64 and theouter piston sleeve 50 (delimited by the longitudinal length of the slot65), the one or more engagement elements 56 can be moved between thefirst (open) position (FIG. 3A) and a second (closed) position (FIG.3B). For example, initial movement of the piston rod 64 in the distaldirection may cause the outer piston sleeve 50 to move distally relativeto the abutment section 52, which is restrained due to the frictionalengagement of the inner piston sleeve 58 with the injector head. Suchrelative movement of the abutment section 52 and the outer piston sleeve50 may cause the one or more engagement elements 56 to be retracted in aradially outward direction to allow the syringe 20 to be removed from(on installed on) the injector 10. Conversely, movement of the pistonrod 64 in the proximal direction may cause the outer piston sleeve 50 tomove proximally relative to the abutment section 52, which is restraineddue to the frictional engagement of the inner piston sleeve 58 with theinjector head 12. Such relative movement of the abutment section 52 andthe outer piston sleeve 50 may cause the one or more engagement elements56 to be extended in a radially inward direction to engage theengagement portion 46 of syringe 20 to allow for retraction of end wall34 and filling of syringe 20.

With continued reference to FIGS. 3A-3B, the engagement elements 56 maybe at least one, and optionally, a plurality of engagement elements 56spaced apart circumferentially around a cavity 78 of the inner pistonsleeve 58. In some examples, a single engagement element 56 may beconfigured to contact the engagement portion 46 of the syringe 20. Theengagement elements 56 may be spaced apart at equal or unequal angularintervals from one another. The engagement elements 56 may be movablebetween a first position (FIG. 3A), where the engagement elements 56 donot contact the engagement portion 46 of the syringe 20, and a secondposition (FIG. 3B), wherein the engagement elements 56 contact the outersurface of the engagement portion 46 of the syringe 20. In someexamples, the engagement elements 56 may have a pointed terminal end 86or tooth configured for at least partially embedding into the materialof the engagement portion 46 of the syringe 20 when the engagementelements 56 are positioned in the second position (FIG. 3B). In someexamples, the engagement elements 56 may be configured to move from thefirst position to the second position immediately upon proximal movementof the piston 19. In other examples, the engagement elements 56 may beconfigured to gradually and progressively move from the first positiontoward the second position with proximal movement of the piston 19 tocontinuously increase the gripping force between the engagement element56 and the engagement portion 46 of the syringe 20. For example, thepointed terminal end 86 may be under a continually increasing force toincrease the “bite” with the engagement portion 46 as the piston ismoved in a proximal direction.

In some examples, the engagement elements 56 may be pivotable about apivot pin 80 on the inner piston sleeve 58 to move the engagementelement 56 between the first position and the second position. Movementof the engagement elements 56 may be constrained by a pin 83 on thecollar 60 that is received within a track 85 on each of the engagementelements 56. The track 85 may be offset from the pivot pin 80 and may beshaped such that it directs the movement of the engagement elements 56between the first and the second position in an arcuate motion about thepivot pin 80. The engagement elements 56 may also be biased by a biasingmechanism (not shown) to one of the first position and the secondposition. To move the engagement elements 56 from the second position tothe first position, at least a portion of each engagement element 56 maybe engaged by the outer engagement surface 54 of the abutment section52. Because the engagement elements 56 are retained on the collar 60,movement of the abutment section 52 relative to the collar 60 causes theouter engagement surface 54 of the abutment section 52 to contact adistal surface of the engagement elements 56. Continued movement of theabutment section 52 relative to the collar 60 causes the engagementelements 56 to be deflected in a radially outward direction to the firstposition. In this manner, the engagement elements 56 can be disengagedfrom contacting the engagement portion 46 of the syringe 20.

Fluid can be delivered from the interior volume 27 of the syringe 20 bydriving the piston 19 in the distal direction. If the interior volume 27of the syringe 20 is fully or partially filled, fluid can be deliveredfrom the syringe 20 by rolling over the sidewall 32 upon itself with thedistal movement of the piston 19. During movement of the piston 19 inthe distal direction, such as shown by arrow A in FIG. 3A, the abutmentsection 52 contacts the proximal surface of the end wall 34 of thesyringe 20. The abutment section 52 is moved to the first positionwithout rolling over the sidewall 32 of the syringe 20 because thepiston rod 64 is moved only to allow the dowel 63 to contact the distalend of the slot 65, thereby moving the engagement elements 56 to thefirst position. In particular, initial distal movement of the piston 19urges the outer engagement surface 54 of the abutment section 52 incontact with at least a portion of each engagement element 56 and causesthe engagement elements 56 to be deflected in a radially outwarddirection, thereby opening a clearance space between the engagementelements 56 to allow insertion or removal of the engagement portion 46of the syringe 20 in the space between the engagement elements 56.

To fill the syringe 20 with fluid, the piston 19 is moved in a proximaldirection in the direction of arrow B in FIG. 3B. During movement of thepiston 19 in the proximal direction, such as shown by arrow B in FIG.3B, the abutment section 52 moves relative to the outer sleeve 50.During such movement, the engagement elements 56 are moved to the secondposition toward the engagement portion 46 of the syringe 20 in aradially inward direction by pivoting about the pivot pin 80. Thepointed terminal end 86 digs into the outer surface of the engagementportion 46 of the syringe 20 as described herein, to provide a grabbingforce between the engagement elements 56 and the engagement portion 46.

FIGS. 5A-5E show the proximal end 30 of the syringe 20 in combinationwith an engagement mechanism 48 of the piston 19 in accordance withvarious aspects of the present disclosure. The components of the syringe20 shown in FIGS. 5A-5E are substantially similar to the components ofthe syringe 20 described herein with reference to FIGS. 2A-2B. Theengagement portion 46 of the syringe 20 is configured for interactingwith one or more engagement elements 56, such as one or more engagementelements 56 of the engagement mechanism 48. The engagement elements 56are configured to move between the first position and the secondposition by moving radially inward and outward to engage and disengage,respectively, the engagement portion 46 of the syringe 20 in a mannersimilar to the engagement of the engagement elements 56 of theengagement mechanism 48 with the engagement portion 46 of the syringe 20described herein with reference to FIGS. 3A-3B.

The engagement mechanism 48 has a drive mechanism 88 for moving theplurality of engagement elements 56 between a first position, whereinthe plurality of engagement elements 56 are disengaged from theengagement portion 46 of the syringe 20, and a second position, whereinthe plurality of engagement elements 56 are engaged with the engagementportion 46 of the syringe 20. The drive mechanism 88 has an outer pistonsleeve 50 and an abutment section 52 fixed relative to the outer pistonsleeve 50 at a distal end thereof. The outer piston sleeve 50 has asubstantially cylindrical structure with an open proximal end and anopen distal end. The abutment section 52 has an outer engagement surface54 for contacting at least a portion of the proximal end 30 of thesyringe 20, such as the end wall 34. An opening 55 is formed in acentral portion of the abutment section 52 and is configured to receiveat least a portion of the engagement portion 46 of the syringe 20 whenthe abutment section 52 contacts the proximal end 30 of the syringe 20.

The drive mechanism 88 further has an inner piston sleeve 58 that isaxially movable relative to the outer piston sleeve 50. The inner pistonsleeve 58 may be biased to the first position (shown in FIG. 5A) or thesecond position (not shown) by a biasing mechanism, such as a spring 79.Movement of the inner piston sleeve 58 in a distal direction and towardthe outer piston sleeve 58 in a direction of arrow A in FIG. 5Bcompresses the spring 79 from a first state (FIG. 5A) to a second state(FIG. 5B).

The inner piston sleeve 58 has a bar or a link 152 with a distal endpivotally movable about a pivot point 154 fixed relative to the outerpiston sleeve 50 and a second end received within a slot 156. Movementof the inner piston sleeve 58 in the distal direction and toward theouter piston sleeve 58 moves the second end of the link 152 from adistal end toward a proximal end of the slot 156 (FIG. 5B). Continuedmovement of the inner piston sleeve 58 in the distal direction andtoward the outer piston sleeve 50 further moves the link 152 proximallywithin the slot 156 such that a distal end 158 of the inner pistonsleeve 58 contacts a proximal end 75 of the engagement elements 56. Thecontact between the distal end 158 of the inner piston sleeve 58 withthe proximal end 75 of the engagement elements 56 urges the engagementelements 56 in a radially inward direction due to the angled shape ofthe distal end 158 of the inner piston sleeve 58 (FIG. 5C). As theengagement elements 56 are urged in a radially inward direction, theengagement elements 56 engage the engagement portion 46 of the syringe20 to allow the end wall 34 of the syringe 20 to be moved in a proximaldirection during filling of the syringe 20. As shown in FIG. 5C, theproximal second end of link 152 is secured in the inverted proximal vee173 of slot 156, reversibly locking the engagement mechanism in thesecond engaged positon with the engagement elements 56 engaged with theengagement portion 46 of syringe 20, for example by where the pointedterminal ends 86 of the engagement elements 56 having dug into thesurface of engagement portion 46. Movement of the engagement elements 56from the first position (FIG. 5A) to the second position (FIG. 5C) maybias an engagement element biasing mechanism, such as a spring 160, froma first position to a second position. In this position (FIG. 5C), thepiston 19 may be retracted in the proximal direction with concomitantunrolling and filling of the syringe 20 with a medical fluid

With reference to FIG. 5D, after retraction of the piston 19 to fillsyringe 20 with the fluid, delivery of the fluid by distal movement ofthe piston 19 also disengages the proximal second end 175 of link 152from the inverted proximal vee 173 of slot 156, at this point movementof the inner piston sleeve 58 in a proximal direction of arrow B afterfluid delivery moves the second end of the link 152 from the proximalend toward the distal end of the slot 156, thereby disengaging thedistal end 158 of the inner piston sleeve 58 from contacting theproximal end 75 of the engagement elements 56. The engagement elements56 can then be retracted to the first position (FIG. 5E) due to therestoring force of the spring 160. Movement of the engagement elements56 from the second position (FIG. 5C) to the first position (FIG. 5D)disengages the engagement elements 56 from the engagement portion 46 ofthe syringe 20 to allow removal of the syringe 20 (FIG. 5E).

With reference to FIGS. 6A-6C, each engagement element 56 may be movablebetween the first position, where the engagement element 56 isdisengaged from the engagement portion 46 of the syringe 20 (not shown),and a second position, where the engagement element 56 is engaged withthe engagement portion 46 of the syringe with axial movement of a drivemechanism 88. The engagement element 56 shown in FIGS. 6A-6C may havethe same structure as the engagement elements 56 shown in FIGS. 3A-3Bincluding pointed terminal ends 86 or teeth for digging into the surfaceof engagement portion 46 to provide a secure connection between theengagement element 56 and engagement portion 46. The engagement element56 may be pivotable about a pivot pin 80. Movement of the engagementelement 56 may be constrained by a pin 83 that is received within atrack 85. The track 85 is offset from the pivot pin 80 and may be shapedsuch that it directs the movement of the engagement elements 56 from thefirst to the second position in an arcuate motion about the pivot pin80. The drive mechanism 88 may be operated by distal and proximalmovement of the piston or may be an activatable drive mechanism, forexample a mechanism that is activated by one or more of a linearelectric motor or actuator, a rotary electric motor or actuator, asolenoid, a pneumatic mechanism, a hydraulic mechanism, anelectromagnetic mechanism, an electroactive polymer mechanism, ashape-memory alloy (such as nitinol wire)-based mechanism, and anycombination thereof.

With continued reference to FIGS. 6A-6C, according the various aspects,the drive mechanism 88 may be formed on or within the piston 19 (notshown). According to certain aspects, the drive mechanism 88 may have afirst sloped surface 88 a and a second sloped surface 88 b axiallyoffset from the first sloped surface 88 a. The first and second slopedsurfaces 88 a, 88 b are angled in a direction pointing radially andproximally away from the engagement portion 46. The drive mechanism 88is movable from a first position (shown in FIG. 6A) to a second position(shown in FIG. 6B) via axial movement in a direction of arrow G in FIG.6A and from the second position to the first position by axial movementin a direction opposite of arrow G. In the first position, the firstsloped surface 88 a is axially offset from a distal end 75 of theengagement element 56. With distal movement of the drive mechanism 88,the first sloped surface 88 a contacts the distal end 75 of theengagement element 56, forcing the distal end 75 to slide along thefirst sloped surface 88 a. Such sliding movement of the distal end 75 ofthe engagement element 56 causes the engagement element 56 to pivotabout the pivot pin 80 and the pin 83 to move from a first end to asecond end of the track 85. The pivoting movement of the engagementelement 56 results in the pointed terminal end 86 moving radially inwardsuch that it contacts the engagement portion 46 of the syringe (FIG.6B). Continued distal movement of the drive mechanism 88 engages thedistal end 75 of the engagement element 56 with the second slopedsurface 88 b (FIG. 6C). Such engagement between the distal end 75 of theengagement element 56 and the second sloped surface 88 b further forcesthe pointed terminal end 86 to move radially inward such that thepointed terminal end 86 digs into and becomes embedded into the materialof the engagement portion 46 of the syringe. With such engagement, thepiston (not shown), can be moved proximally and retract the engagementportion 46 and distal end 30 of syringe 20 (see FIGS. 2A-2B), to fillthe syringe with fluid, as described herein with reference to FIGS.3A-3B.

FIGS. 7A-7B show the proximal end 30 of the syringe 20 in combinationwith an engagement mechanism 48 of the piston 19 in accordance withvarious examples of the present disclosure. The components of syringe 20shown in FIGS. 7A-7B are substantially similar to the components of thesyringe 20 described herein with reference to FIGS. 2A-2B. Theengagement portion 46 of the syringe 20 is configured for interactingwith one or more engagement elements, such as one or more engagementelements 56 of the engagement mechanism 48. The engagement elements 56are configured to move radially inward and outward to engage anddisengage, respectively, the engagement portion 46 of the syringe 20 ina manner similar to the engagement of the engagement elements 56 of theengagement mechanism 48 with the engagement portion 46 of the syringe 20described herein with reference to FIGS. 3A-3B. According to variousembodiments, the inward/outward movement of the engagement elements 56in FIGS. 7A-7B may occur independently of the proximal/distal movementof the piston 19 due to operation of a drive mechanism 88.

With continued reference to FIGS. 7A-7B, the drive mechanism 88 isconfigured for controlling the movement of the engagement elements 56between a first, or disengaged position (FIG. 7A) and a second, engagedposition (FIG. 7B). The drive mechanism 88 is disposed within the outerpiston sleeve 50. Similar to the piston 19 shown in FIGS. 3A-3B, thepiston 19 in FIGS. 7A-7B has the abutment section 52 at a distal endthereof for engaging with the end wall 34 of the syringe 20. Activationof the drive mechanism 88 moves the abutment section 52 relative to theouter sleeve 50, such as by advancing the abutment section 52 in adistal direction. Such movement of the abutment section 52 moves theengagement elements 56 in a radially inward direction to engage theengagement portion 46 of the syringe 20. The engagement elements 56 maybe movable between a first position (FIG. 7A), where the engagementelements 56 do not contact the engagement portion 46 of the syringe 20,and a second position (FIG. 7B), wherein the engagement elements 56contact the outer surface of the engagement portion 46 of the syringe 20and the pointed terminal end 86 digs into and becomes embedded into thematerial of the engagement portion 46. In some examples, radial movementof the engagement elements 56 may further be a function of proximalmovement of the piston 19 in a direction of arrow B shown in FIG. 7B.That is, as the piston 19 is moved further in the proximal direction,the force of the “bite” or radially inward force between the engagementelements 56 and the pointed terminal ends 86 with the engagement portion46 increases so that any proximal slipping of the pointed terminal ends86 through the material of the engagement portion 46 is counteracted.For example, during initial movement of the piston 19 in the proximaldirection, the engagement elements 56 may be advanced radially inward toan initial contact position where the engagement elements 56 contact theouter surface of the engagement portion 46 of the syringe 20. Withcontinued proximal movement of the piston 19, the engagement elements 56may continue to move in a radially inward direction from the initialcontact position such that the engagement elements 56 and pointedterminal ends 86 dig into or become embedded within the material of theengagement portion 46 of the syringe 20 to increase the holding force onthe syringe 20. The engagement elements 56 may move to a final contactposition having a maximum radial displacement from the initial contactposition at a final proximal position of the piston 19. In otherexamples, radial movement of the engagement elements 56 may becontrolled independent of the proximal or distal movement of the piston19. A linkage mechanism 73 connects the drive mechanism 88 with theengagement elements 56 to effect the movement of the engagement elements56 with actuation of the drive mechanism 88.

Various embodiments of the drive mechanism 88 may be mechanically,electrically, pneumatically, and/or hydraulically operated. For example,the drive mechanism 88 may have an electric or electromechanicalmechanism, such as a linear or rotary electric motor, or a solenoid. Inother examples, the drive mechanism 88 may be activated/deactivated byan electromagnetic mechanism, an electroactive polymer mechanism, or ashape-memory alloy (such as nitinol wire)-based mechanism. Variouscombinations of these mechanisms is also contemplated at being withinthe scope of the present disclosure. In some examples, the drivemechanism 88 may be selectively energized, such as during proximal ordistal movement of the piston 19. In other examples, the drive mechanism88 may be constantly energized, regardless of whether the piston 19 isstationary, or moving in the proximal or distal direction.

In certain embodiments, movement of the drive mechanism 88 relative tothe outer piston sleeve 50 is configured to allow engagement ordisengagement of the engagement elements 56 with engagement portion 46of the syringe 20. In some examples, movement of the abutment section 52in a proximal direction relative to the outer piston sleeve 50 and awaythe syringe 20 may result in the drive mechanism 88 retracting theengagement elements 56 in a radially outward direction to allow thesyringe 20 to be removed from the injector 10. Conversely, movement ofthe abutment section 52 in a distal direction relative to the outerpiston sleeve 50 and toward the syringe 20 may result in the drivemechanism 88 extending the engagement elements 56 in a radially inwarddirection to engage the engagement portion 46 of the syringe 20. Inother examples, operation or activation of the drive mechanism 88 may beindependent of the movement of the abutment section 52, the outer pistonsleeve 50, and/or the piston 19, such that the engagement elements 56can be selectively moved between the first position and the secondposition based upon operation of the drive mechanism 88 only.

FIGS. 8A-8C show the proximal end 30 of the syringe 20 in combinationwith an engagement mechanism 48 of the piston 19 in accordance withvarious examples of the present disclosure. The components of thesyringe 20 shown in FIGS. 8A-8C are substantially similar to thecomponents of the syringe 20 described herein with reference to FIGS.2A-2B. The engagement portion 46 of the syringe 20 is configured forinteracting with one or more engagement elements, such as one or moreengagement elements 56 of the engagement mechanism 48. The engagementelements 56 are configured to move radially inward and outward to engageand disengage, respectively, the engagement portion 46 of the syringe 20in a manner similar to the movement of the engagement elements 56relative to the engagement portion 46 of the syringe 20 described hereinwith reference to FIGS. 3A-3B.

Radial movement of the engagement elements 56 may be controlledindependently of the proximal or distal movement of the piston 19. Forexample, after the piston 19 is advanced in a distal direction such thatthe abutment section 52 contacts the proximal end 30 of the syringe 20,the engagement elements 56 may be advanced radially inward withactuation of the drive mechanism 88, such as a solenoid operated piston188. In some examples, the drive mechanism 88 may rotate each of theengagement elements 56 about the pivot pin 80 in a direction of arrows Cin FIG. 8B to engage (FIG. 8A) or disengage (FIG. 8C) the engagementelements 56 from the engagement portion 46. The engagement elements 56may be biased to move in a radially inward direction from their initialposition to a final position due to a biasing mechanism such as aspring. Movement of the engagement elements 56 radially inwardly maycause the material of the engagement portion 46 of the syringe 20 is atleast partially deformed. For example, the engagement elements 56 may beat least partially embedded into the material of the engagement portion46 such that the post of the engagement portion 46 is deformed from itsinitial configuration (FIG. 8A) to a final configuration (FIGS. 8B-8C)due to the force applied by the biasing mechanism. In some examples, thedeformed engagement portion 46 may have an inverted “T” shape, whereinthe engagement elements 56 engage at least a portion of the deformedengagement portion 46. Activation of the solenoid operated piston 188moves the solenoid operated piston 188 in a distal direction, causingthe engagement elements to move against the biasing force of the biasingmechanism and actively engage or disengage from the engagement portion46.

FIGS. 9A-9D show the proximal end 30 of the syringe 20 in combinationwith an engagement mechanism 48 of the piston 19 in accordance withother examples of the present disclosure. The components of the syringe20 shown in FIGS. 9A-9D are substantially similar to the components ofthe syringe 20 described herein with reference to FIGS. 2A-2B. Theengagement portion 46 of the syringe 20 is configured for interactingwith one or more engagement elements, such as one or more engagementelements 56, of the engagement mechanism 48. The engagement elements 56are configured to move radially inward and outward to engage anddisengage, respectively, the engagement portion 46 of the syringe 20 ina manner similar to the movement of the engagement elements 56 relativeto the engagement portion 46 of the syringe 20 described herein withreference to FIGS. 3A-3B.

With continued reference to FIGS. 9A-9D, the engagement mechanism 48 hasa drive mechanism 88 for moving the plurality of engagement elements 56between a first position, wherein the plurality of engagement elements56 are disengaged from the engagement portion 46 of the syringe 20, anda second position, wherein the plurality of engagement elements 56 areengaged with the engagement portion 46 of the syringe 20. The engagementmechanism 48 has an outer piston sleeve 50 and an abutment section 52fixed relative to the outer piston sleeve 50 at a distal end thereof.The outer piston sleeve 50 has a substantially cylindrical structurewith an open proximal end and an open distal end. The abutment section52 has an outer engagement surface 54 for contacting at least a portionof the proximal end 30 of the syringe 20, such as the end wall 34. Anopening 55 is formed in a central portion of the abutment section 52 andis configured to receive at least a portion of the engagement portion 46of the syringe 20 when abutment section 52 contacts the syringe 20.

The engagement mechanism 48 further has an inner piston sleeve 58 thatis axially movable relative to the outer piston sleeve 50. The innerpiston sleeve 58 may be biased to a first position (shown in FIG. 9A) bya biasing mechanism, such as a spring 79. Movement of the inner pistonsleeve 58 in a distal direction and relative to the outer piston sleeve58 in a direction of arrow A in FIG. 9B compresses the spring 79 from afirst state (FIG. 9A) to a second state (FIG. 9B).

With continued reference to FIGS. 9A-9D, the drive mechanism 88 has asolenoid 165 having a two or more locking levers 166 at a proximal endof the solenoid 165. Each locking lever 166 is rotatably mounted on apivot pin 168 such that each locking lever 166 is rotatable about thepivot pin 168. In some examples, the locking levers 166 may be biased ina radially outward direction by a biasing mechanism (not shown).Proximal ends of the locking levers 166 are configured for beingreceived within a groove 170 on an inside surface of the outer pistonsleeve 50. Movement of the inner piston sleeve 58 in the distaldirection relative to the outer piston sleeve 58, such as due tomovement of the piston 19, moves the locking levers 166 to a positionwhere the locking levers 166 can be expanded radially outward byrotating in a direction of arrow C in FIG. 9B when the locking levers166 are axially aligned within the groove 170. Movement of the lockinglevers 166 in a radially outward direction into the groove 170 locks thelocking levers 166, and thereby the inner piston sleeve 58 from movingproximally relative to the outer piston sleeve 50. Distal movement ofthe inner piston sleeve 58 relative to the outer piston sleeve 50 ispermitted due to an angled surface 172 of the groove 170 deflecting theproximal ends of the locking levers 166 in a radially inward direction(FIG. 9C).

Concurrent with movement of the inner piston sleeve 58 in the distaldirection relative to the outer piston sleeve 58, the inner pistonsleeve 58 urges a distal end 158 of the inner piston sleeve 58 tocontact a proximal end 75 of the engagement elements 56. Contact betweenthe distal end 158 of the inner piston sleeve 58 with the proximal end75 of the engagement elements 56 urges distal ends of the engagementelements 56 and the pointed terminal ends 86 in a radially inwarddirection due to the angled shape of the distal end 158 of the innerpiston sleeve 58 with the proximal end 75 of the engagement elements 56(FIG. 9C). As the engagement elements 56 are urged in a radially inwarddirection, the engagement elements 56 engage the engagement portion 46of the syringe 20 to allow the end wall 34 of the syringe 20 to be movedin a proximal direction during filling of the syringe 20 and in a distaldirection during a fluid delivery from syringe 20. Movement of theengagement elements 56 from the first position (FIG. 9A) to the secondposition (FIG. 9C) may bias an engagement element biasing mechanism,such as a spring 160, from a first position to a second position.

With reference to FIG. 9D, when the solenoid 165 is energized, thelocking levers 166 are rotated about the pivot pins 168 radially inwardin a direction of arrow D, thereby disengaging the proximal ends of thelocking levers 166 from the grooves 170. This allows the inner pistonsleeve 58 to be moved proximally relative to the outer piston sleeve 50,thereby disengaging the distal end 158 of the inner piston sleeve 58from contacting the proximal end 75 of the engagement elements 56. Theengagement elements 56 are subsequently retracted to the first position(FIG. 9D), for example due to the restoring force of the spring 160.Movement of the engagement elements 56 from the second position (FIG.9C) to the first position (FIG. 9D) disengages the engagement elements56 from the engagement portion 46 of the syringe 20 to allow removal ofthe syringe 20.

FIGS. 10A-10D show the proximal end 30 of the syringe 20 in combinationwith an engagement mechanism 48 of the piston 19 in accordance withvarious aspects of the present disclosure. The components of the syringe20 shown in FIGS. 10A-10D are substantially similar or identical to thecomponents of the syringe 20 described herein with reference to FIGS.2A-2B. The engagement portion 46 of the syringe 20 is configured forinteracting with one or more surfaces of the engagement mechanism 48that engage and disengage the engagement portion 46 of the syringe 20with movement of a central rod 37. For example, the engagement portion46 of the syringe 20 is configured for interacting with one or moreengagement elements 56, such as one or more engagement arms 68, of theengagement mechanism 48 that move radially inward and outward to engageand disengage, respectively, the engagement portion 46 of the syringe20.

In various examples, the engagement mechanism 48 has the one or moreengagement elements 56, such as the one or more engagement arms 68,movable in a radial direction relative to the engagement portion of thesyringe 20 between a first position, where the engagement arms 68 aredisengaged from the engagement portion 46 of the syringe 20, and asecond position, where the engagement arms 68 are engaged with theengagement portion 46 of the syringe 20. The engagement mechanism 48further has a drive mechanism 88 for moving the engagement arms 68between the first position and the second position.

The engagement arms 68 each include a proximal end 69 configured forinteracting with a central rod 37 operably connected to the piston 19. Adistal end 70 of the engagement arms 68 is configured for engagementwith the engagement portion 46 of the syringe 20. Each arm 68 ispivotable about a pivot pin 80 between a first position, where theengagement portion 46 of the syringe 20 can be freely inserted into andremoved from the space between the arms 68, a second position, such asan opening 55 in an outer engagement surface 54 of the piston 19,wherein the distal end 70 of the arms 68 engages at least a portion ofthe engagement portion 46 of the syringe 20, for example by digging oneor more pointed terminal ends 86 into a surface of the engagementportion 46. In the example shown in FIGS. 10A-10D, the central rod 37 isconfigured to move relative to the piston 19 in the proximal/distaldirection. FIGS. 10A-10B show the central rod 37 in a proximallyretracted position, such that the engagement arms 68 are disengaged fromthe engagement portion 46 of the syringe 20. FIGS. 10C-10D show thecentral rod 37 in a distally extended position, such that a widenedportion of central rod 37 abuts the proximal ends 69 of the engagementarms 68, causing the engagement arms 68 to rotate about respective pivotpins 80 to engage the distal end 70 of the engagement arms 68 with theengagement portion 46 of the syringe 20. In various examples,proximal/distal movement of the central rod 37 may be effected by and/ordependent upon proximal/distal movement of the piston 19. In otherexamples, proximal/distal movement of central rod 37 may be independentof the proximal/distal movement of piston 19, such as by a drivemechanism 88 substantially similar or identical to the drive mechanism88, such as any of the drive mechanisms described herein.

With reference to FIG. 10B, the central rod 37 has a proximal portion 37a having a first diameter that is larger than a space between theengagement arms 68 and a distal portion 37 b having a second diameterthat is smaller or equal to the space between the engagement arms 68,when the engagement arms 68 are in the first position. The proximal anddistal portions 37 a, 37 b may be connected by a ramp 37 c. Theengagement arms 68 are positioned in the first position away from theengagement portion 46 of the syringe 20 when the distal portion 37 b ofthe central rod 37 is positioned between the proximal ends 69 of theengagement arms 68. With a distal movement of the central rod 37, suchas due to actuation of the drive mechanism 88, the ramp 37 c engages theproximal ends 69 of the engagement arms 68 to spread the proximal ends69 radially apart from each other to allow the proximal portion 37 a ofthe central rod 37 to be inserted therebetween. Spreading of theproximal ends 69 of the engagement arms 68 moves the distal ends 70thereof radially closer together and into engagement with the engagementportion 46 of the syringe 20 into the second positon. Proximalretraction of the central rod 37 reverses the process and disengages thedistal ends 70 from the engagement portion 46 of the syringe 20 to allowremoval of the syringe 20 from the injector. In some examples, a biasingmechanism, such as a spring, may be provided to bias the engagement armsto the first (open) position or the second (closed) position.

According to other aspects, such as shown in FIGS. 10E-10F, the centralrod 37 has a proximal portion 37 a having a first diameter that issmaller than a space between the engagement arms 68 and a distal portion37 b having a second diameter that is larger or equal to the spacebetween the engagement arms 68. The proximal and distal portions 37 a,37 b may be connected by the ramp 37 c. The engagement arms 68 arepositioned away from the engagement portion 46 of the syringe 20 whenthe proximal portion 37 a of the central rod 37 is positioned betweenthe proximal ends 69 of the engagement arms 68. With a proximal movementof the central rod 37, such as due to actuation of the drive mechanism88, the ramp 37 c engages the proximal ends 69 of the engagement arms 68to spread the proximal ends 69 apart from each other to allow the distalportion 37 b of the central rod 37 to be inserted therebetween.Spreading of the proximal ends 69 of the engagement arms 68 moves thedistal ends 70 thereof closer together and into engagement with theengagement portion 46 of the syringe 20. Distal extension of the centralrod 37 reverses the process and disengages the distal ends 70 from theengagement portion 46 of the syringe 20 to allow removal of the syringe20 from the injector.

In further examples, the central rod 37 may have a conical shape withouta distinct ramp 37 c between the proximal and distal portions 37 a, 37b, respectively. The central rod 37 may be movable in a proximaldirection with actuation of the drive mechanism 88 to engage theengagement arms 68 with the engagement portion 46 of the syringe 20. Inother examples, central rod 37 may be movable in a distal direction withactuation of drive mechanism 88 to engage engagement arms 68 with theengagement portion 46 of syringe 20.

In some examples, such as shown in FIGS. 10G-10H, the central rod 37 mayhave two or more links 41 a, 41 b pivotally connected at their first endto a distal end 37 d of the central rod 37. A second end of each link 41a, 41 b is pivotally connected to a proximal end 69 of one of theengagement arms 68. In this manner, movement of the central rod 37 in aproximal/distal direction causes the links 41 a, 41 b to pivot abouttheir pivot points on the distal end 37 d of the central rod 37 and theproximal ends 69 of the engagement arms 68. In certain embodiments, thelength of each of the two links 41 a, 41 b may be selected such thatwhen the links 41 a, 41 b are oriented substantially perpendicular to alongitudinal axis of the central rod 37, the distal ends 70 of theengagement arms 68 are engaged with the engagement portion 46 of thesyringe 20 (FIG. 10H). With movement of the central rod 37 in a proximaldirection or distal direction from the position shown in FIG. 10H, thelinks 41 a, 41 b are pivoted to a second position, wherein distal ends70 of the engagement arms 68 are disengaged from the engagement portion46 of the syringe 20. In other embodiments, the length of each of thetwo links 41 a, 41 b may be selected such that the links 41 a, 41 bremain angled relative to a longitudinal axis of the central rod 37 whenthe distal ends 70 of the engagement arms 68 are engaged with theengagement portion 46 of the syringe 20 (not shown). According to theseembodiments, further proximal retraction of the piston may also causeretraction of the central rod 37 relative to the links 41 a, 41 b,causing links 41 a, 41 b to apply a further radially extending force tothe proximal ends 69 of the engagement arms 68 and creating a greaterengagement or “biting” force between the distal ends 70 of theengagement arms 68 with the engagement portion 46 of the syringe 20.

According to other examples, as shown in FIGS. 11A-11D, the central rod37 may have an elliptical, oval, or rectangular cam 38 positionedbetween the proximal ends 69 of the engagement arms 68. The cam 38 has aminor axis and a major axis, wherein the minor axis is shorter than themajor axis. The central rod 37 may be rotatable about its longitudinalaxis between a disengaged, first position shown in FIGS. 11A-11B and anengaged, second position shown in FIGS. 11C-11D. In the disengaged,first position, the central rod 37 is positioned such that the proximalends 69 of the engagement arms 68 are substantially aligned parallelwith a minor axis of the cam 38. In the engaged, second position, thecentral rod 37 is rotated about the longitudinal axis such that theproximal ends 69 of the engagement arms 68 are substantially alignedparallel with the major axis of the cam 38, causing the proximal ends 69to move radially outward with respect to the central rod 37. Spreadingof the proximal ends 69 of the engagement arms 68 moves the distal ends70 thereof closer together and into engagement with the engagementportion 46 of the syringe 20, resulting in digging one or more pointedterminal ends 86 into a surface of the engagement portion 46. Rotationof the central rod 37 between the major and minor axes being inalignment with the proximal ends 69 of the engagement arms 68selectively moves the mechanism between the first, disengaged positionand the second, engaged position. Rotation of the central rod 37 may beeffected by a drive mechanism 88, such as by a drive mechanism 88substantially similar or identical to the drive mechanism 88, such asany of the drive mechanisms described herein.

In other examples similar to that depicted in FIGS. 11A-11D, the cam 38may be substituted with a disc having slots each corresponding to andinteracting with the proximal end 69 of one of the engagement arms 68.In particular, each slot defines a track for the proximal ends 69, suchthat as the disc is rotated by the drive mechanism 88, the proximal ends69 of the engagement arms 68 are caused to move radially outward andinward with respect to the central rod 37. Consequently, the engagementarms 68 are forced to rotate about respective pivot pins 80 to engagethe engagement portion 46 of the syringe 20.

Referring now to FIG. 12 , an engagement mechanism 48 in accordance withother aspects of the present disclosure is shown in combination with theproximal end 30 of a syringe 20. The components of the syringe 20 shownin FIG. 12 are substantially similar or identical to the components ofthe syringe 20 described herein with reference to FIGS. 2A-2B. Theengagement mechanism 48 includes one or more engagement arms 68rotatable around respective pivot pins 80, substantially similar to theengagement arms 68 and pivot pins 80 described herein with reference toFIGS. 10A-11D. The engagement arms 68 differ from those of FIGS. 10A-11Din that the each engagement arm 68 further includes a lobe 71 betweenthe proximal and distal ends of the engagement arm 68. The lobe 71 ofeach engagement arm 68 is configured to interact with a deactivating pin74 moveable in the proximal/distal direction. In an unlocked state shownin FIG. 12 , the deactivating pin 74 is extended in the distal directionsuch that the lobe 71 of each engagement arm 68 abuts the deactivatingpin 74, thereby preventing the distal ends 70 of the respectiveengagement arms 68 from engaging the engagement portion 46 of thesyringe 20. The deactivating pin 74 may be retracted in the proximaldirection to achieve a locked position in which the lobes 71 aredisengaged from the deactivating pin 74 and the pointed terminal ends 86of the engagement arms 68 are permitted to engage the engagement portion46 of the syringe 20 by rotation around pivot pins 80.

Proximal/distal movement of the deactivating pin 74 may be controlled bya drive mechanism, substantially similar or identical to the drivemechanism 88 described herein with reference to FIGS. 7A-7B. In someembodiments, the engagement arms 68 may be biased toward the lockedposition (i.e., normally closed) such that additional mechanisms are notrequired to maintain engagement between the engagement arms 68 and theengagement portion 46 of the syringe 20. In other embodiments, theengagement arms 68 may be biased toward the unlocked position (i.e.,normally open) such that actuation of the deactivating pin 74 or anotheractuation mechanism is required to engage the engagement arms 68 withthe engagement portion 46 of the syringe 20.

With reference to FIG. 13 , an engagement mechanism 48 of a piston 19 isshown in accordance with other examples of the present disclosure. Theengagement mechanism 48 includes at least a pair of engagement arms 68that are pivotally connected to the piston 19 via a cam member 15. Inone example, the engagement arms 68 are configured to move between anopen first position and a closed second position to grip the engagementportion 46 of the syringe 20. A band 23, may be configured as anelectro-active polymer is positioned on each of the engagement arms 68.In some examples, the band 23 may be a nitinol wire or othershape-memory alloy. To move the engagement arms 68 from the openposition to the closed position, an electrical charge may be applied ordirected to the band 23 to cause the band 23 to contract, therebyreducing the diameter of the band 23. As the band 23 is contracted, theengagement arms 68 are brought towards one another to clamp on theengagement portion 46 of the syringe 20.

While examples of a fluid delivery system and a syringe for use thereforwere provided in the foregoing description, those skilled in the art maymake modifications and alterations to these examples without departingfrom the scope and spirit of the disclosure. Accordingly, the foregoingdescription is intended to be illustrative rather than restrictive. Thedisclosure described hereinabove is defined by the appended claims, andall changes to the disclosure that fall within the meaning and the rangeof equivalency of the claims are to be embraced within their scope.

We claim:
 1. An engagement mechanism associated with a reciprocallymovable piston of a fluid injector and configured for releasablyengaging an engagement portion at a proximal end of a rolling diaphragmsyringe, wherein the rolling diaphragm syringe comprises a flexiblesidewall configured for rolling upon itself when acted upon by thereciprocally movable piston, the engagement mechanism comprising: aplurality of engagement elements, wherein each engagement element isreversibly and pivotally movable about a respective pivot pin relativeto the engagement portion of the syringe between a first position, wherethe plurality of engagement elements are disengaged from the engagementportion of the syringe, and a second position, where the plurality ofengagement elements are pivotally moved in a radially inward directionto engage with the engagement portion of the syringe, and wherein atleast one of the plurality of engagement elements has a pointed distalend configured for at least partially embedding into the engagementportion of the syringe when the plurality of engagement elements are inthe second position; and a drive mechanism for moving the plurality ofengagement elements between the first position and the second position.2. The engagement mechanism of claim 1, wherein the plurality ofengagement elements are progressively movable from the first position tothe second position with movement of the reciprocally movable piston ina proximal direction to continuously increase a gripping force on theengagement portion of the syringe.
 3. The engagement mechanism of claim1, wherein the drive mechanism is operatively connected to thereciprocally movable piston such that the plurality of engagementelements are movable from the first position to the second position withmovement of the reciprocally movable piston in a proximal direction. 4.The engagement mechanism of claim 3, wherein the plurality of engagementelements are movable from the second position to the first position withmovement of the reciprocally movable piston in a distal direction. 5.The engagement mechanism of claim 1, wherein the drive mechanism movesthe plurality of engagement elements between the first position and thesecond position independently of movement of the reciprocally movablepiston in a proximal direction or a distal direction.
 6. The engagementmechanism of claim 1, wherein the drive mechanism comprises at least oneof a linear electric motor or actuator, a rotary electric motor oractuator, a solenoid, a pneumatic mechanism, a hydraulic mechanism, anelectromagnetic mechanism, an electroactive polymer mechanism, a nitinolwire-based mechanism, and any combination thereof.
 7. The engagementmechanism of claim 1, wherein the drive mechanism comprises a rodlinearly or rotatably movable by a motor, and wherein linear or rotarymovement of the rod reversibly moves the plurality of engagementelements between the first position and the second position.
 8. Theengagement mechanism of claim 1, wherein the plurality of engagementelements are biased to one of the first position or the second positionby a biasing mechanism.
 9. The engagement mechanism of claim 8, whereinthe biasing mechanism is a spring.
 10. An engagement mechanismassociated with a reciprocally movable piston of a fluid injector andconfigured for releasably engaging an engagement portion at a proximalend of a rolling diaphragm syringe, wherein the rolling diaphragmsyringe comprises a flexible sidewall configured for rolling upon itselfwhen acted upon by the reciprocally movable piston, the engagementmechanism comprising: a plurality of engagement elements, wherein eachengagement element is reversibly and pivotally movable about arespective pivot pin relative to the engagement portion of the syringebetween a first position, where the plurality of engagement elements aredisengaged from the engagement portion of the syringe, and a secondposition, where the plurality of engagement elements are pivotally movedin a radially inward direction to engage with the engagement portion ofthe syringe, and wherein at least one of the plurality of engagementelements has a pointed distal end configured for at least partiallyembedding into the engagement portion of the syringe when the pluralityof engagement elements are in the second position; and a drive mechanismfor moving the plurality of engagement elements between the firstposition and the second position, the drive mechanism comprising: anouter piston sleeve fixed relative to the reciprocally movable piston ofthe fluid injector; an abutment section movably received within theouter piston sleeve at a distal end of the outer piston sleeve, whereinthe abutment section is operatively engaged with the plurality ofengagement elements; and an inner piston sleeve movably received withinthe outer piston sleeve and connected with the abutment section suchthat movement of the inner piston sleeve causes movement of the abutmentsection, wherein the inner piston sleeve is movable by a piston rodmovably coupled to the reciprocally movable piston, wherein movement ofthe reciprocally movable piston in a proximal direction moves the outerpiston sleeve proximally relative to the abutment section, and whereinproximal movement of the outer piston sleeve relative to the abutmentsection moves the plurality of engagement elements from the firstposition to the second position.
 11. The engagement mechanism of claim10, wherein the abutment section has an outer engagement surfaceconfigured for contacting a closed end wall of the syringe and a centralopening on the outer engagement surface configured for receiving theengagement portion of the syringe.
 12. The engagement mechanism of claim10, wherein the plurality of engagement elements are progressivelymovable from the first position to the second position with movement ofthe reciprocally movable piston in the proximal direction tocontinuously increase a gripping force on the engagement portion of thesyringe.
 13. The engagement mechanism of claim 10, wherein the pluralityof engagement elements are movable from the second position to the firstposition with movement of the reciprocally movable piston in the distaldirection.
 14. The engagement mechanism of claim 10, wherein theplurality of engagement elements are biased to one of the first positionor the second position by a biasing mechanism.
 15. The engagementmechanism of claim 14, wherein the biasing mechanism is a spring.
 16. Afluid injector comprising: at least one injector head comprising atleast one reciprocally movable piston; an engagement mechanismassociated with the at least one reciprocally movable piston andconfigured for releasably engaging an engagement portion at a proximalend of a rolling diaphragm syringe, wherein the rolling diaphragmsyringe comprises a flexible sidewall configured for rolling upon itselfwhen acted upon by the at least one reciprocally movable piston, theengagement mechanism comprising: a plurality of engagement elements,wherein each engagement element is reversibly and pivotally movableabout a respective pivot pin relative to the engagement portion of thesyringe between a first position, where the plurality of engagementelements are disengaged from the engagement portion of the syringe, anda second position, where the plurality of engagement elements arepivotally moved in a radially inward direction to engage with theengagement portion of the syringe, and wherein at least one of theplurality of engagement elements has a pointed distal end configured forat least partially embedding into the engagement portion of the syringewhen the plurality of engagement elements are in the second position;and a drive mechanism for moving the plurality of engagement elementsbetween the first position and the second position.
 17. The fluidinjector of claim 16, wherein the drive mechanism comprises at least oneof a linear electric motor or actuator, a rotary electric motor oractuator, a solenoid, a pneumatic mechanism, a hydraulic mechanism, anelectromagnetic mechanism, an electroactive polymer mechanism, a nitinolwire-based mechanism, and any combination thereof.
 18. The fluidinjector of claim 16, wherein the drive mechanism comprises a rodlinearly or rotatably movable by a motor, and wherein linear or rotarymovement of the rod reversibly moves the plurality of engagementelements between the first position and the second position.
 19. Thefluid injector of claim 16, wherein the drive mechanism comprises: anouter piston sleeve fixed relative to the at least one reciprocallymovable piston of the fluid injector; an abutment section movablyreceived within the outer piston sleeve at a distal end of the outerpiston sleeve, wherein the abutment section is operatively engaged withthe plurality of engagement elements; and an inner piston sleeve movablyreceived within the outer piston sleeve and connected with the abutmentsection such that movement of the inner piston sleeve causes movement ofthe abutment section, wherein the inner piston sleeve is movable by apiston rod movably coupled to the at least one reciprocally movablepiston, wherein movement of the at least one reciprocally movable pistonin a proximal direction moves the outer piston sleeve proximallyrelative to the abutment section, and wherein proximal movement of theouter piston sleeve relative to the abutment section moves the pluralityof engagement elements from the first position to the second position.